This invention relates to an adjustable anti-roll mechanism which is particularly suited for an open wheel style racing car.
Racing cars are regularly subjected to harsh cornering maneuvers which tend to roll the vehicle about the roll or longitudinal axis thereof. Accordingly, the vehicle suspension system must exhibit roll stiffness, or resistance to roll around the roll axis of the vehicle. These types of vehicles have suspension systems which include an anti-roll mechanism, which resists this tendency of the vehicle to roll during cornering, while still accommodating normal vehicle riding motions in which wheels on opposite sides of the vehicle move substantially equally and all significant vehicle suspension movement is about the pitch axis of the vehicle. Race cars may have two separate anti-roll mechanisms, one of which controls the roll stiffness of the rear wheel suspension and the other controlling the roll stiffness of the front wheel suspension. Conventionally, the driver may adjust the roll stiffness of the vehicle suspension during racing by operating a control in the cockpit.
Drivers commonly complain that existing adjustable roll control mechanisms are xe2x80x9cnon-linearxe2x80x9d, that is, that a given adjustment of the control in the cockpit does not always result in a corresponding change in roll stiffness. Drivers also complain that the roll stiffness does not feel constant during cornering, so that the handling characteristics of the car change during cornering, making the car unstable. Both of these complaints are the result of deflections inherent in prior anti-roll mechanisms.
According to the present invention, vehicle suspension movements are transmitted to an anti-roll mechanism which is pivotally mounted on the vehicle for movement about the pitch axis thereof to accommodate normal ride motion of the vehicle in which wheels on opposite sides of the vehicle move equally. The anti-roll mechanism includes a torsion bar which is loaded by suspension movement. Roll stiffness is controlled by adjusting the lever arm through which suspension movement is transmitted to the torsion bar by a lever arrangement commonly referred to as a Watt""s link to assure that the change in the length of the lever arm is directly proportional to the change in the control in the cockpit. Accordingly, linear control is assured, and the torsion bar and lever arms to not appreciable deflect during cornering. While the invention is particularly described as being used in a racing car, other vehicles, such as passenger cars and similar vehicles may also benefit from the present invention.